Contaminated water treatment

Abstract

Method and system for processing of a liquid (“contaminant liquid”) containing water and containing urine and/or other contaminants in a two step process. Urine, or a contaminated liquid similar to and/or containing urine and thus having a relatively high salt and urea content is passed through an activated carbon filter to provide a resulting liquid, to remove most of the organic molecules. The resulting liquid is passed through a semipermeable membrane from a membrane first side to a membrane second side, where a fortified drink having a lower water concentration (higher osmotic potential) than the resulting liquid is positioned. Osmotic pressure differential causes the water, but not most of the remaining inorganic (salts) contaminant(s) to pass through the membrane to the fortified drink. Optionally, the resulting liquid is allowed to precipitate additional organic molecules before passage through the membrane.

1. A method for treatment of a liquid containing urea, the method comprising:
 receiving a liquid containing urea (urea containing liquid or “UCL”), having a salt content of at least 5 gm/liter and having a total organic content (“TOC”) of at least 2500 mg/liter; 
 passing the UCL through an activated carbon filter to produce an intermediate liquid, in which at least 90 percent of organic molecules have been removed, within about one hour after the UCL was generated; 
 providing a semipermeable membrane, having a first side and a second side, and being selected to allow passage therethrough of water in the intermediate liquid in a direction that tends to equalize osmotic potential of water on the first and second sides of the membrane; 
 positioning the intermediate liquid in contact with at least a portion of the membrane first side; 
 positioning a concentrated fortified drink, having a higher liquid osmotic potential for water than a UCL osmotic potential for water on the membrane first side, in contact with at least a portion of the membrane second side; and 
 allowing a portion of the intermediate liquid to pass through the membrane from the first side to the second side to tend to reduce an imbalance of osmotic potential of the liquids on the first and second sides of the membrane, and to produce a processed liquid having a TOC of no more than 25-50 mg/liter. 
 
     
     
       2. The method of  claim 1 , further comprising collecting at least a portion of a mixture of said fortified drink and said water that has passed through said membrane, on said membrane second side. 
     
     
       3. The method of  claim 1 , further comprising maintaining or increasing salinity of said UCL before passing said UCL through said activated carbon filter, to promote additional removal of organic molecules by said activated carbon filter. 
     
     
       4. The method of  claim 1 , further comprising providing a hydrophilic membrane as said semipermeable membrane. 
     
     
       5. The method of  claim 1 , further comprising providing a hydrophobic membrane as said semipermeable membrane. 
     
     
       6. The method of  claim 1 , further comprising adjusting pH of said UCL after passing said UCL through said activated carbon filter, to promote separation of a selected contaminant from said by said membrane. 
     
     
       7. The method of  claim 1 , further comprising removing at least 95 percent of urea from said UCL. 
     
     
       8. The method of  claim 5 , further comprising removing at least 99 percent of said urea from said UCL.